Microbes R Us

The ecosystem withinRecent research has established that 90% of the cells in our bodies are not our own. They belong to microbes — bacteria and other microscopic creatures, collectively known as our microbiome.

Like good guests who help with cooking and clean-up, many of these microbes perform valuable, not to say, essential services, providing enzymes for digestion, vitamins, anti-inflammatory agents and other compounds that we need but cannot produce ourselves. There may be some bad guys among them — microorganisms such as E. coli that we usually think of as pathogens — but in a healthy body, they seem to do no harm.

In fact, our microbiomes give us an exponentially larger gene pool to work with to perform necessary bodily functions. And like our DNA itself, our microbiomes are unique to us.

Not only is the emerging science around this subject fascinating, but it is upending traditional ideas of sickness and health.

Read The Ecosystem Within to learn about your microbiome and what you can do to keep it (and yourself) fit.


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9 Responses to Microbes R Us

  1. Julie August 29, 2012 at 12:41 pm #

    I dont understand a scientific statement centered
    Around microbes living in us that could possibly
    Believe that i do NOT share those with my unborn
    Children, ir, for that matter, that conception itself
    Has no active & influencing microbes as well
    How is this a sane assumption?

    • Sheryl August 29, 2012 at 3:47 pm #

      Julie, I’m not sure I understand your question. Are you saying it doesn’t make sense that your microbes are not shared with your unborn child? Because if so, you’re right. Your microbes *are* shared as part of the birth process. But until your water breaks, your womb provides the baby with a largely sterile environment. (It is possible for a woman’s uterine defenses to be breached, but that is not typical.)


  2. Evan Hazard August 29, 2012 at 5:35 pm #

    “Technically, they’re parasites.” No, unless they’ve changed the terminology since I retired in ’94 after 36 years as a biology prof, technically they are mutualists.

    • Sheryl August 29, 2012 at 7:39 pm #

      Well, technically, they’re not all mutualists either. In any event, using the word “technically” was my real crime.

      • Bernadette August 31, 2012 at 11:37 am #

        Well, technically, they are symbionts. Depending on the environmental (abiotic and biotic) conditions, they may be beneficial (mutualistic), detrimental (parasitic), or neutral (commensalistic) with respect to our well-being. I think symbiotic is the safest bet, since they do satisfy the basic definition of symbiosis in all cases.

  3. Galen Guerrero-Murphy August 29, 2012 at 10:25 pm #

    Sheryl, I just discovered your blog and admire it! See my recent (and similar) post on Biodiversity of Self: We Are More Than “Us” at BioResilience.com

    In blogging on this topic myself, I had a similar reaction as Julie (commenter)–just hard to believe fetuses are sterile, with no microbiomes until they emerge at birth! Thanks, Julie, for challenging this assumption–it inspired me to dig a bit deeper. Well, as it turns out there is mounting evidence that microbiome formation begins well before birth, within the previously-thought-to-be sterile amniotic environment of the womb! See here, here, here and here.

    Also, to address perhaps a subtlety of Julia’s comments–a mother contributes to the child’s microbiome directly with microbes (both before and during birth), but there is evidence that the genetic makeup of your child will also affect what microbial communities takes hold (as might physical factors, diet, etc)–this is another way mothers “contribute” to the child’s microbiome.

    We are each unique habitats for microbes. I suspect “my habitat” is more similar to my parents’ habitat than yours, and, hence, microbes that establish in my habitat will be more similar to my parents.

    This would help explain why families share similar microbiomes (e.g., this article).

    I love this particularly illuminating quote from Pilar et al 2012 on the dynamics of the microbiome: “…maternally inherited populations detected in the infant at one month had been lost by 11 months, suggesting that early colonizers can be easily replaced by externally acquired species. Such dynamics limit the potential for development of long-term coadaptations between specific bacterial and host genotypes. Rather, an intermittent pattern of interactions between different strains and human genotypes is likely to result in a diffuse process of coevolution among all interacting partners.”

    What a great topic!

  4. Suzanne August 30, 2012 at 6:31 am #


    Thank you for your exceptional article! These are things I have been trying to tell friends, relatives & colleagues for years now! As many things are being written about the dangers of our universe there has been a tendency for people to pull away from outdoor activities. This limits our exposure to all the organism that are continuing to adapt as we hide inside our homes and office buildings instead of allowing our bodies to absorb and adapt as well. We become essentially a “bubble boy” so disinfected that we cannot with-stand contact with our own universe. Excellent article!


  5. Bernadette August 31, 2012 at 11:49 am #

    I think that one point needs some further explanation in your article:” …even a low, short-term dose of antibiotics increases antibiotic-resistant genes in the animals, including genes resistant to antibiotics not even administered, which can be passed onto you through the meat.”
    Not quite – the resistance genes in the animals (I’m assuming you are referring to members of the Kingdom Animalia at that point, so we’ll assume you mean the bovines) do not change based on whether antibiotics are administered. It is the evolution of the microbes in response to strong selection by antibiotics that causes resistance genes to increase in frequency. Yes, these can be passed along in association with the meat. I read the primary lit article too – that’s pretty much what it says.
    Also, the changes in the microbes that causes them to be resistant to the antibiotics administered can provide a cross-resistance to other antibiotics that were not administered, and that is perhaps the really scary part! (You mentioned this but only in passing.) We only have so many mechanisms by which antibiotics work, so even when new ones are developed, they may be encountering populations of microbes that will already be resistant to them, via cross-resistance. Our arsenal of antibiotics is not infinite – and we seem to be reaching the end of our capacity to come up with new ways to deal with harmful microbes.

    • Sheryl August 31, 2012 at 1:06 pm #

      Yes, that sentence wasn’t clear and needs rewriting. I didn’t notice until someone emailed me about it yesterday. I plan to resend a corrected version of the mailer next week and update the webpage.

      The piece was already too long and detailed for the main audience, so I couldn’t get into the cross-resistance issue in any depth, though I agree, it really is the scariest part.

      Thanks for your careful reading and comments.